System of radio telephony and telegraphy



Sept. 3, .1935. H. s. POLIN 7 2,013,173

SYSTEM OF RADIO TELEPHONY AND IELE(Prl'iAPHY Filed Oct. 31, 1929 Patented Sept. 3, 1935 UNITED STATES mm OFFIQEQP,

sYs'rEMor RADIO TELEPHONY AND T TELEGRAPHY Herbert S. Polin, San Francisco, Calif., assignor, by direct and mcsne assignments, to International Radiophone Corporation, Washington, D. 0., a corporation of Delaware Application October 31, 1929, Sc1'ial No. 403,717 1 18 Claims. (01. 250- 9) f This invention relates to improvements in high frequency telephone transmitting and receiving systems and apparatus.

in accordance with a principal feature the invention provides a system for transmitting and receiving signals wherein each station comprises synchronously tuned vacuum tube transmitterand receiver units adapted to oscillate at a common carrier frequency in synchronism with each other and with the corresponding units of other stations, whereby two-way intercommunication between stations may be eifected on the common carrier frequency.

An important aspect of the invention is that at a given station one antenna is operatively associated with both the transmitter and the receiver. That is to say', the transmitter and the receiver use the same aerial and the same ground. The transmitting unit and the receiving unit are coupled preferably both inductively anddirectly to the antenna circuit.

A very important feature of the invention is that the transmitter and receiver at a'given stamitter, and regcneratively amplified by the transmitter as well as by the receiver, so that the wave or signal, as receivedand detected represents a summation of the combined regenerative amplitying action of thetransmitter and of the receiver. This cooperative interaction just described between transmitter and receiver is achieved in part by virtue of the mentioned direct and inductive coupling of both transmitter and receiver to the common antenna.

important feature of the antenna circuit is that it is provided with a wave conductor tuning unit, which acts as a' micrometric Wave filter, and allows the passage, in either direction, only of waves having a very definite and accurately predetermined frequency, and no other waves. This wave conductor-tuningmnit may be in the form of a solenoidal coil which is finely or micrometrically adiusted and tuned to allow the'pa'ssage of energy of thedesired frequency,. and no others. p

The transmitting unit at, the one station has exactly the same characteristics as the transy mitting unit at the other station, and the receiving unit at the one station has exactly the same characteristics as the receiving unit at the other station. At each station,the transmitting and re ceiving units, are, as stated, synchronously tuned with respect to each other as well as synchronously in tune with their counterparts at the opposing station. The tuning elements inthe antenna at the respective stations are accurately tuned to pass waves of the samepredetermined frequency only. Both stations, therefore, transmit and receive on a common carrier frequency, and none other. There is thus set up between stations a field of radiantenergy of this same frequency, and all the tubes at both stations are caused thereby to oscillate in synchronism at this frequency.

To describe further the regenerative amplification of a signal Wave at a given stationt--On receiving, incoming modulated carrier wave signals impinging on the antenna are simultaneously impressed on the associated transmitter and receiver units thereat, in such manner that each regeneratively amplifies the portion of the signal energy applied thereto. Due to the mentioned direct connection and inductive coupling between units to the common antenna circuit; the transmitting and receiving portions react upon one another at both'the carrier and modulating frequencies'iurther to intensify or amplify the signals. The signals ultimately .detected thus embody a summation of the individual regenerative amplifying effectsof the transmitter and receiver units, togetherwith their cooperative amplifying action. Likewise on transmitting, the modulated wave created in the transmitter portion is re: generatively amplified thereby, and also independ ently as well as cooperatively by the associated receiver'unit as a result of the inductive and direct couplings betweenunits operative at both the carrier and modulating frequencies. The V ultimate wave thus radiated from the antenna accordinglycomprises a summation of these; several amplifying effects. 7 i I This regeneration -of the incoming. waves by the operation of the transmitting unit at-the receiving station enables the'receiving station effectively to receive relatively much weaker sig--' nals than otherwisewith consequent increase in range of reception. Another obvious result' is that less power need be used at the opposing transmitting station for a given range.

Certain circuit features of the present invention are disclosed in my copending application Serial Number 364,838, filed May 21, 1929.

For the purpose of illustration, the figure on the drawing shows two stations A and B, station A having a transmitter T and receiver R, and station B having a transmitter T and receiver R.

Referring now to transmitter portion T of station A, the antenna l is connected to solenoidal coil 2, adjustably mounted with respect to the metal plate 3; this plate is connected to one terminal of coil 4, the other terminal of which is conducted to ground ll. The elements 2 and 3 are relatively adjustable and act as a wave conductor tuning unit achieving a resonance tuning and serving as a micrometric wave filter, which will allow the passage, in either direction, of waves of only a definite pre-determined frequency, and no other waves. The coil 4 is inductively coupled to coil 5.

A screen grid tube 6, has its plate 1', connected by conductor 8, to one terminal of coil 5, the other terminal of which is connected to the positive terminal of the high voltage power source 8, by conductor is. Tapped from an intermediate potential point of the high voltage power source 9, is conductor II, the other terminal of which is connected to the screen grid l2, of tube 6.

Grid I3 is connected by conductor 14 to one terminal of the crystal oscillator 35, the other terminal of which is connected by conductor 53 to ground ll. Another conductor i8, leads from grid l3 through choke l9 and grid leak resistance 20 to one terminal of the output winding 2| of a transformer or induction coil the other end of which goes to ground IT. This transformer has a core 22 and a primary coil 2-3. A microphone of any desired type 24, in series with a suitable power source 25, is interposed in this primary circuit as shown.

The cathode 26, of the screen grid tube 6 is provided with a suitable energizing means 2? and is connected through conductor 30 to ground. A condenser 28 is interposed between cathode 25 and conductor H, as shown. A circuit comprising conductor 8, variable condenser 23 and conductor 14, forms a shunt between the grid l3 and plate 1, as shown.

The receiving unit R of station A is also inductively coupled to the antenna circuit comprising antenna I, solenoidal coil 2 and metal plate by conductor 3| which is connected to one terminal of coil 32 the other terminal of which is grounded at IT.

A screen grid tube 34 which comprises a grid 35, screen grid 36, cathode 3'! and plate 38, has its cathode provided with suitable energizing means 39 and is connected through conductor ,40 to ground IT. A condenser, 4!, is interposed between cathode 31 and conductor 42 as shown. A circuit comprising conductor 43, condenser 45 and conductor 44 forms a shunt between the plate 38 and grid 35 of tube 34 as shown. The screen grid 33 is connected through conductor 42 to an intermediate potential point of a source of power 46. The plate circuit of this tube comprises a source of power 46, the negative terminal'of which is connected to ground ll through ear phones 4! and conductor 48. The positive terminal of said power source 45 is connected through coil 49 and conductor 44 to plate 38. I

The grid 35 of this tube is connected by conductor 43 and coil 33 (which is inductively coupled to coil 32) to the negative side of a power source 59, the positive terminal of which is grounded at 5?. This power source furnishes a negative bias to grid 35 of tube 34.

The transmitter unit and the receiver unit are also directly connected by conductors 39, 3| and 48, so that incoming or outgoing signals are impressed on and amplified by both units, whereby during transmission T and R act as transmitters, and during reception T and P. act as receivers.

Station B is a substantial duplicate of station A; each station operates in the same way in sending and receiving; and corresponding parts are indicated by primed reference characters.

The operation oi the circuit as shown in the illustration is as follows: Upon the closing of all circuits oscillations will initiate in the circuits of the tubes 6 and 34 which may have a fundamental frequency predetermined by the characteristics of crystal l5. These oscillations, taking character from the voice impressed upon the microphone 24, will be impressed upon the grid of tube 6. This tube will amplify said oscillations and impress these said amplified oscillations on the outputcoil 5 which is inductively coupled to antenna coil 4. The impressed wave will be conducted through coil. 3 and inductively passed to wave conductor coil 2 through plate 3 to antenna I and thence into space.

Simultaneously the modulating frequencies originating in the microphone 24 are applied directly to the grid of receiver tube 34 over the circuit comprising direct connections 3t-3i--48 and the inductive coupling between coils 32 and 33, and thus modulate the high frequency oscillations generated by the receiver. Also the modulated high frequency oscillations originating in the transmitter T are applied through inductive couplings 5 t and 32-33 and the common antenna circuit, to the receiver R to be regeneratively amplified thereby. The resulting amplified signals of the receiver are thereupon fed back into the antenna system and radiated therefrom.

The energy producing these oscillations is de-- rived from a source of current here shown as a battery, although it will be understood that this showing is purely diagrammatic and any suitable source of power may be employed.

It will further be understood that, while for convenience of illustration, various distinct sources of current are shown, in practice, many or all or" these may be combined so that all pow-er is derived from a single source.

Throughout the two stations, an exceedingly fine tuning of identical apparatus, each to the other, has placed these stations in synchronous adjustment and the insertion of resonance tuning makes for an additional micromatic filter in an already super selective circuit. In operation, there is set up between the two antennas, a band of radiant energy of a predetermined accurate frequency and all units of the two stations are placed in absolute synehronism. I have found that the action of the opposing'stations, under this new arrangement of transmitting and receiving units, permits intercommunication without the necessity of making inoperative the whole or any portion or" the transmitting or receiving units during intercommunication between the two stations.

The high selectivity of this circuit which is resonance tuned and the synchronization achieved by the exact-tuning f the individual portions, of the apparatus make-for. the absorption and eliminationof all types of interference. The pre-determined frequency. channel is open to itssynchronously operated station and it alone,

permitting .secrecy otvoperation"on this band.

The two transmitters and 'the itwo receivers are designed. to oscillate in synchronism; This is assured by suitable adjustments of the tuning elements, and'by constructing the crystal controls for the several "stationsto havelike characte r is'tics. "The transmitting and receiving units at each station aresoclosely interconnected. be-

ing connected directly and "inductively as has been described, as t'o maintain syntony of oscillation therein despite p ossible slight difierences or maladjustment oftilned frequencies for the transmittingand'receiving units respectively. In other v'vords; the coupling between transmitting and receiving-unitsis such that they will pull into step and maintain a common oscillation fre- Another new andunusual result of operation with this 'circuitis itspperative efiiciency for radio phone communication on an extremely low 'wai edength and at a' frequency heretofore assumed to be impractical for this purpose.

An incoming wave is received in the receiver R in the usual way. [However. "since the transmitterT, as jwellthe receiver R isinductively and 7 directly coupled to the same antenna circuit, an important'ncw result is attained. in that the same incomingjfvvave impresses its characterjon the transmitter T and is amplified and regenerated by this'transmitter and fed backinto coils and t and thence into coilsfltzand 33. and thence into the "receiver R, thereby strengthening. regen- .e ating and amplifying the'energy received by communication withits opposing station. N

This unit combination, asjdescribed. has for an additional purpose. the provision of a valve or filter in any transmitting or receiving circuit. Inserted in the antenna circuit between the aerial and couplin of standard transmitter, and/or receiving units. it permits the passage only of energy of pre-determined frequency.

While for purposes of illustration and simplicity. two tubes are shown in the drawing which illustrates a simple receiving and transmitting circu t. it is readily understood that if and when functioning as a valve. the unit is operative. both for transmitting and receiving. with but one tube as part of the unit. This unit maintains synchronous relation with its counterpart at the opposing station. That is to say, the functions of transmitting and receiving described for the two tubes, can be performed by a single tube acting as an appurtenance to the receiving and transmitting circuit.

It should beunderstood that the invention disclosed can equally well be used in radiotelegraphy, in which case, a telegraphic key could be used in place of the microphone circuit.

The invention has been disclosed only diagrammatically and in its present preferred form. It should be understood that the disclosure is illustrative, and not restrictive of the invention, and that the inventive concept may be carried out in various other ways, as falling within the scope of the appended claims.

sand

I claim as my invention: 1. A combined radio telephone transmitting receiving apparatus, comprising in combination a transmitting unit and a receiving unit, an

antenna inductively coupled to both units, and

means directly connecting both units to the antenna, whereby incoming waves are impressed upon both units, the waves impressed upon the transmitting unit being fed inductively back into the receiving unit, whereby the waves are thu regenerated and amplified.

2; A combined radio telephone transmitting receiving apparatus, comprising :incombination synchronously tuned transmitting and receiving units, an antenna common to both units, a wave conductor tuning unit interposed in the antenna circuit, whereby incoming Waves are impressed upon both units, the waves impressed upon the transmitting unit being fedinductively back into the receiving unit, whereby the waves are thus regenerated and amplified.

A combined radio telephone transmitting and receiving apparatus, comprising in combination a transmitting unit, a receiving unit, a

conductor directly connected and inductively coupled to both units, aresonance tuning unit interposed in the conductor circuit, whereby incoming waves are impressed upon both units, the waves impressed upon the transmitting unit being fed inductvely back into the receiving unit, whereby the waves are thus regenerated andsamplified.

A combined radio telephone transmitting and receiving apparatus, comprising in combina- "tion a transmitting unit, a receiving unit, an antenna directly connected and inductively coupled to both units, a wave conductor tuning unit interposed in the antenna circuit, the tuning unit serving to filter the waves passing through it and to permit the passage only of waves of a definite frequency, whereby incoming waves are impressed uponboth units, the waves impressed upon the transmittin unit being fed inductively back into the receiving unit, whereby the waves are thus regenerated and amplified.

5 A radio telephone system which comprises a combined transmitter unit'and receiver unit, said units being tuned synchronously, and means directly connecting the units to each other so that a received signal is amplified not only by the re ceiver unit but also by the transmitter unit associated therewith.

A radio telephone system for transmitting and receiving signals which comprises a combined transmitter unit and receiver unit, said units being adapted to oscillate in synchronism with each other, and means inter-connecting the two units whereby a portion of a received signal is picked up by the transmitter and. impressed on the receiver.

'l. A radio telephone system for transmitting and receiving signals which comprises a combined transmitter unit and receiver unit, said units being adapted to oscillate in synchronism with each other, and means inter-connecting the two units whereby a portion of a received signal is picked up by the transmitter and amplified, the signal thus amplified being impressed on the receiver.

8. A radio telephone system for transmitting and receiving signals which comprises a transmitter unit and receiver unit adapted to oscillate in synchronism with each other and means for directly connecting and inductively coupling the transmitter unit to the receiver unit so that during operation both units cooperate in the reception of signals.

9. A radio telephone system for transmitting and receiving signals which comprises a combined transmitter unit and receiver unit, said units being adapted to oscillate in synchronism with each other, means for directly connecting said units to each other so that at least a portion of the received signal is regenerated and amplified by the transmitter unit and impressed on the receiver unit and means for inductively coupling the transmitter unit to the receiver unit so that during operation both units cooperate in the reception of signals.

10. A radio telephone system for transmitting and receiving signals which comprises a combined transmitter unit and receiver unit, said units being adapted to oscillate in synchronism with each other, means for directly connecting and inductively coupling the transmitter unit to the receiver unit so that an impressed signal is regenerated and amplified by the transmitter unit, the signal thus regenerated and amplified being impressed on the associated receiver unit, and thus added to the same signal as is amplified by the receiver unit.

11. A radio telephone system for transmitting and receiving signals which comprises a combined transmitter unit and receiver unit, said units being adapted to oscillate in synchronism with each other, means for connecting the said units whereby a received signal is regenerated and amplified by the transmitter unit and the signal thus received and amplified is inductively and directly impressed upon the receiver unit, and so is added to the said received signal amplified by the receiver unit.

12. A radio telephone system for transmitting and receiving signals which comprises a combined transmitter unit and receiver unit, said units being adapted to oscillate in synchronism with each other, an antenna directly connected to the said units and means for inductively coupling the transmitter unit and the receiver unit to the common antenna.

13. A radio telephone system for transmitting and receiving signals which comprises a combined transmitter unit and receiver unit adapted to oscillate in synchronism with each other, means for directly connecting the said units to each other so that at least a portion of a received signal is regenerated and amplified by the transmitter unit and impressed on the receiver unit, an

antenna for the said units, and means for di--'- rectly and inductively coupling the said units to the said antenna.

14. A radio telephone system for transmitting and receiving signals which comprises a combined transmitter unit and receiver unit adapted to oscillate in synchronism with each other, an antenna connecting the transmitter unit to the receiver unit so that during reception a portion of a received signal is picked up by the transmitter and impressed on the receiver.

15. A radio telephone system for transmitting and receiving signals which comprises a plurality of stations, each station having a transmitter unit and a receiver unit all adapted to oscillate in synchronism with each other, means for directly connecting the units of each station to each other so that at least a portion of a received signal is regenerated and amplified by the transmitter unit of the receiving station and is impressed on the receiver unit thereof, each station of the system cap-able of adjustment to synchronism with other stations thereof.

16. High frequency signaling apparatus comprising in combination, a regenerative signal transmitting device, a regenerative signal receiving device, and means so coupling said devices that each regenerates the signal of the other.

17. High frequency signaling apparatus comprising in combination, a regenerative signal transmitting device, a regenerative signal receiving device, and means so coupling said devices to a common antenna that each regenerates the signals of the other whereby said devices c0- operatively amplify transmitted and received signals.

18. A duplex radio system comprising a crystal controlled oscillating transmitter unit, an oscillating receiver unit, and coupling means therebetween adapting said units to oscillate in syncronism, whereby the crystal control of the transmitter controls the oscillating frequency of the receiver.

HERBERT S. POLIN. 

